The AB system is the major blood group system in domestic cats. The common blood types are A and B. Cats with blood type A have naturally occurring anti-B antibodies at a low titer and cats with blood type B have naturally occurring anti-A antibodies at a high titer. A third rare type  AB  is also known.
An HVAC technician can install, repair, and provide maintenance on heating and air conditioning systems. Exterior wall vent leading to an HVAC system. HVAC technicians install, repair and maintain heating, cooling and venting systems.HVAC technicians are expected to be skilled in air conditioner repair.hen an HVAC technician is associated with the installation of a new system, he or she will be proficient in reading blueprints connected to the installation, and will participate in the preparation of the space for the installation of the required equipment.
A high level of work is required of an HVAC technician. There is a specific complexity to temperature control systems within the HVAC field. A formal education and certification is a job requirement for most, if not all, HVAC companies. Along with classes, apprenticeships provide valuable hands-on training.